From fb34a9ae383ae26326d4889fd2513e49f1019b88 Mon Sep 17 00:00:00 2001
From: Zhiyong Tao <zhiyong.tao@mediatek.com>
Date: Fri, 24 Sep 2021 16:06:31 +0800
Subject: [PATCH] pinctrl: mediatek: support rsel feature

This patch supports rsel(resistance selection) feature for I2C pins.
It provides more resistance selection solution in different ICs.
It provides rsel define and si unit solution by identifying
"mediatek,rsel_resistance_in_si_unit" property in pio dtsi node.

Signed-off-by: Zhiyong Tao <zhiyong.tao@mediatek.com>
Reviewed-by: Chen-Yu Tsai <wenst@chromium.org>
Link: https://lore.kernel.org/r/20210924080632.28410-5-zhiyong.tao@mediatek.com
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
---
 .../pinctrl/mediatek/pinctrl-mtk-common-v2.c  | 231 +++++++++++++++---
 .../pinctrl/mediatek/pinctrl-mtk-common-v2.h  |  46 ++++
 drivers/pinctrl/mediatek/pinctrl-paris.c      |  60 +++--
 3 files changed, 289 insertions(+), 48 deletions(-)

--- a/drivers/pinctrl/mediatek/pinctrl-mtk-common-v2.c
+++ b/drivers/pinctrl/mediatek/pinctrl-mtk-common-v2.c
@@ -665,6 +665,181 @@ out:
 	return err;
 }
 
+static int mtk_hw_pin_rsel_lookup(struct mtk_pinctrl *hw,
+				  const struct mtk_pin_desc *desc,
+				  u32 pullup, u32 arg, u32 *rsel_val)
+{
+	const struct mtk_pin_rsel *rsel;
+	int check;
+	bool found = false;
+
+	rsel = hw->soc->pin_rsel;
+
+	for (check = 0; check <= hw->soc->npin_rsel - 1; check++) {
+		if (desc->number >= rsel[check].s_pin &&
+		    desc->number <= rsel[check].e_pin) {
+			if (pullup) {
+				if (rsel[check].up_rsel == arg) {
+					found = true;
+					*rsel_val = rsel[check].rsel_index;
+					break;
+				}
+			} else {
+				if (rsel[check].down_rsel == arg) {
+					found = true;
+					*rsel_val = rsel[check].rsel_index;
+					break;
+				}
+			}
+		}
+	}
+
+	if (!found) {
+		dev_err(hw->dev, "Not support rsel value %d Ohm for pin = %d (%s)\n",
+			arg, desc->number, desc->name);
+		return -ENOTSUPP;
+	}
+
+	return 0;
+}
+
+static int mtk_pinconf_bias_set_rsel(struct mtk_pinctrl *hw,
+				     const struct mtk_pin_desc *desc,
+				     u32 pullup, u32 arg)
+{
+	int err, rsel_val;
+
+	if (hw->rsel_si_unit) {
+		/* find pin rsel_index from pin_rsel array*/
+		err = mtk_hw_pin_rsel_lookup(hw, desc, pullup, arg, &rsel_val);
+		if (err)
+			goto out;
+	} else {
+		if (arg < MTK_PULL_SET_RSEL_000 ||
+		    arg > MTK_PULL_SET_RSEL_111) {
+			err = -EINVAL;
+			goto out;
+		}
+
+		rsel_val = arg - MTK_PULL_SET_RSEL_000;
+	}
+
+	err = mtk_hw_set_value(hw, desc, PINCTRL_PIN_REG_RSEL, rsel_val);
+	if (err)
+		goto out;
+
+	err = mtk_pinconf_bias_set_pu_pd(hw, desc, pullup, MTK_ENABLE);
+
+out:
+	return err;
+}
+
+int mtk_pinconf_bias_set_combo(struct mtk_pinctrl *hw,
+			       const struct mtk_pin_desc *desc,
+			       u32 pullup, u32 arg)
+{
+	int err = -ENOTSUPP;
+	u32 try_all_type;
+
+	if (hw->soc->pull_type)
+		try_all_type = hw->soc->pull_type[desc->number];
+	else
+		try_all_type = MTK_PULL_TYPE_MASK;
+
+	if (try_all_type & MTK_PULL_RSEL_TYPE) {
+		err = mtk_pinconf_bias_set_rsel(hw, desc, pullup, arg);
+		if (!err)
+			return err;
+	}
+
+	if (try_all_type & MTK_PULL_PU_PD_TYPE) {
+		err = mtk_pinconf_bias_set_pu_pd(hw, desc, pullup, arg);
+		if (!err)
+			return err;
+	}
+
+	if (try_all_type & MTK_PULL_PULLSEL_TYPE) {
+		err = mtk_pinconf_bias_set_pullsel_pullen(hw, desc,
+							  pullup, arg);
+		if (!err)
+			return err;
+	}
+
+	if (try_all_type & MTK_PULL_PUPD_R1R0_TYPE)
+		err = mtk_pinconf_bias_set_pupd_r1_r0(hw, desc, pullup, arg);
+
+	if (err)
+		dev_err(hw->dev, "Invalid pull argument\n");
+
+	return err;
+}
+EXPORT_SYMBOL_GPL(mtk_pinconf_bias_set_combo);
+
+static int mtk_rsel_get_si_unit(struct mtk_pinctrl *hw,
+				const struct mtk_pin_desc *desc,
+				u32 pullup, u32 rsel_val, u32 *si_unit)
+{
+	const struct mtk_pin_rsel *rsel;
+	int check;
+
+	rsel = hw->soc->pin_rsel;
+
+	for (check = 0; check <= hw->soc->npin_rsel - 1; check++) {
+		if (desc->number >= rsel[check].s_pin &&
+		    desc->number <= rsel[check].e_pin) {
+			if (rsel_val == rsel[check].rsel_index) {
+				if (pullup)
+					*si_unit = rsel[check].up_rsel;
+				else
+					*si_unit = rsel[check].down_rsel;
+				break;
+			}
+		}
+	}
+
+	return 0;
+}
+
+static int mtk_pinconf_bias_get_rsel(struct mtk_pinctrl *hw,
+				     const struct mtk_pin_desc *desc,
+				     u32 *pullup, u32 *enable)
+{
+	int pu, pd, rsel, err;
+
+	err = mtk_hw_get_value(hw, desc, PINCTRL_PIN_REG_RSEL, &rsel);
+	if (err)
+		goto out;
+
+	err = mtk_hw_get_value(hw, desc, PINCTRL_PIN_REG_PU, &pu);
+	if (err)
+		goto out;
+
+	err = mtk_hw_get_value(hw, desc, PINCTRL_PIN_REG_PD, &pd);
+
+	if (pu == 0 && pd == 0) {
+		*pullup = 0;
+		*enable = MTK_DISABLE;
+	} else if (pu == 1 && pd == 0) {
+		*pullup = 1;
+		if (hw->rsel_si_unit)
+			mtk_rsel_get_si_unit(hw, desc, *pullup, rsel, enable);
+		else
+			*enable = rsel + MTK_PULL_SET_RSEL_000;
+	} else if (pu == 0 && pd == 1) {
+		*pullup = 0;
+		if (hw->rsel_si_unit)
+			mtk_rsel_get_si_unit(hw, desc, *pullup, rsel, enable);
+		else
+			*enable = rsel + MTK_PULL_SET_RSEL_000;
+	} else {
+		err = -EINVAL;
+		goto out;
+	}
+
+out:
+	return err;
+}
+
 static int mtk_pinconf_bias_get_pu_pd(struct mtk_pinctrl *hw,
 				const struct mtk_pin_desc *desc,
 				u32 *pullup, u32 *enable)
@@ -746,44 +921,40 @@ out:
 	return err;
 }
 
-int mtk_pinconf_bias_set_combo(struct mtk_pinctrl *hw,
-				const struct mtk_pin_desc *desc,
-				u32 pullup, u32 arg)
-{
-	int err;
-
-	err = mtk_pinconf_bias_set_pu_pd(hw, desc, pullup, arg);
-	if (!err)
-		goto out;
-
-	err = mtk_pinconf_bias_set_pullsel_pullen(hw, desc, pullup, arg);
-	if (!err)
-		goto out;
-
-	err = mtk_pinconf_bias_set_pupd_r1_r0(hw, desc, pullup, arg);
-
-out:
-	return err;
-}
-EXPORT_SYMBOL_GPL(mtk_pinconf_bias_set_combo);
-
 int mtk_pinconf_bias_get_combo(struct mtk_pinctrl *hw,
 			      const struct mtk_pin_desc *desc,
 			      u32 *pullup, u32 *enable)
 {
-	int err;
+	int err = -ENOTSUPP;
+	u32 try_all_type;
 
-	err = mtk_pinconf_bias_get_pu_pd(hw, desc, pullup, enable);
-	if (!err)
-		goto out;
+	if (hw->soc->pull_type)
+		try_all_type = hw->soc->pull_type[desc->number];
+	else
+		try_all_type = MTK_PULL_TYPE_MASK;
 
-	err = mtk_pinconf_bias_get_pullsel_pullen(hw, desc, pullup, enable);
-	if (!err)
-		goto out;
+	if (try_all_type & MTK_PULL_RSEL_TYPE) {
+		err = mtk_pinconf_bias_get_rsel(hw, desc, pullup, enable);
+		if (!err)
+			return err;
+	}
+
+	if (try_all_type & MTK_PULL_PU_PD_TYPE) {
+		err = mtk_pinconf_bias_get_pu_pd(hw, desc, pullup, enable);
+		if (!err)
+			return err;
+	}
+
+	if (try_all_type & MTK_PULL_PULLSEL_TYPE) {
+		err = mtk_pinconf_bias_get_pullsel_pullen(hw, desc,
+							  pullup, enable);
+		if (!err)
+			return err;
+	}
 
-	err = mtk_pinconf_bias_get_pupd_r1_r0(hw, desc, pullup, enable);
+	if (try_all_type & MTK_PULL_PUPD_R1R0_TYPE)
+		err = mtk_pinconf_bias_get_pupd_r1_r0(hw, desc, pullup, enable);
 
-out:
 	return err;
 }
 EXPORT_SYMBOL_GPL(mtk_pinconf_bias_get_combo);
--- a/drivers/pinctrl/mediatek/pinctrl-mtk-common-v2.h
+++ b/drivers/pinctrl/mediatek/pinctrl-mtk-common-v2.h
@@ -17,6 +17,22 @@
 #define MTK_ENABLE     1
 #define MTK_PULLDOWN   0
 #define MTK_PULLUP     1
+#define MTK_PULL_PU_PD_TYPE		BIT(0)
+#define MTK_PULL_PULLSEL_TYPE		BIT(1)
+#define MTK_PULL_PUPD_R1R0_TYPE		BIT(2)
+/* MTK_PULL_RSEL_TYPE can select resistance and can be
+ * turned on/off itself. But it can't be selected pull up/down
+ */
+#define MTK_PULL_RSEL_TYPE		BIT(3)
+/* MTK_PULL_PU_PD_RSEL_TYPE is a type which is controlled by
+ * MTK_PULL_PU_PD_TYPE and MTK_PULL_RSEL_TYPE.
+ */
+#define MTK_PULL_PU_PD_RSEL_TYPE	(MTK_PULL_PU_PD_TYPE \
+					| MTK_PULL_RSEL_TYPE)
+#define MTK_PULL_TYPE_MASK	(MTK_PULL_PU_PD_TYPE |\
+				 MTK_PULL_PULLSEL_TYPE |\
+				 MTK_PULL_PUPD_R1R0_TYPE |\
+				 MTK_PULL_RSEL_TYPE)
 
 #define EINT_NA	U16_MAX
 #define NO_EINT_SUPPORT	EINT_NA
@@ -42,6 +58,14 @@
 	PIN_FIELD_CALC(_s_pin, _e_pin, 0, _s_addr, _x_addrs, _s_bit,	\
 		       _x_bits, 32, 1)
 
+#define PIN_RSEL(_s_pin, _e_pin, _rsel_index, _up_resl, _down_rsel) {	\
+		.s_pin = _s_pin,					\
+		.e_pin = _e_pin,					\
+		.rsel_index = _rsel_index,				\
+		.up_rsel = _up_resl,					\
+		.down_rsel = _down_rsel,				\
+	}
+
 /* List these attributes which could be modified for the pin */
 enum {
 	PINCTRL_PIN_REG_MODE,
@@ -67,6 +91,7 @@ enum {
 	PINCTRL_PIN_REG_DRV_E0,
 	PINCTRL_PIN_REG_DRV_E1,
 	PINCTRL_PIN_REG_DRV_ADV,
+	PINCTRL_PIN_REG_RSEL,
 	PINCTRL_PIN_REG_MAX,
 };
 
@@ -129,6 +154,22 @@ struct mtk_pin_field_calc {
 	u8  fixed;
 };
 
+/**
+ * struct mtk_pin_rsel - the structure that provides bias resistance selection.
+ * @s_pin:		the start pin within the rsel range
+ * @e_pin:		the end pin within the rsel range
+ * @rsel_index:	the rsel bias resistance index
+ * @up_rsel:	the pullup rsel bias resistance value
+ * @down_rsel:	the pulldown rsel bias resistance value
+ */
+struct mtk_pin_rsel {
+	u16 s_pin;
+	u16 e_pin;
+	u16 rsel_index;
+	u32 up_rsel;
+	u32 down_rsel;
+};
+
 /* struct mtk_pin_reg_calc - the structure that holds all ranges used to
  *			     determine which register the pin would make use of
  *			     for certain pin attribute.
@@ -206,6 +247,9 @@ struct mtk_pin_soc {
 	bool				ies_present;
 	const char * const		*base_names;
 	unsigned int			nbase_names;
+	const unsigned int		*pull_type;
+	const struct mtk_pin_rsel	*pin_rsel;
+	unsigned int			npin_rsel;
 
 	/* Specific pinconfig operations */
 	int (*bias_disable_set)(struct mtk_pinctrl *hw,
@@ -254,6 +298,8 @@ struct mtk_pinctrl {
 	const char          **grp_names;
 	/* lock pin's register resource to avoid multiple threads issue*/
 	spinlock_t lock;
+	/* identify rsel setting by si unit or rsel define in dts node */
+	bool rsel_si_unit;
 };
 
 void mtk_rmw(struct mtk_pinctrl *pctl, u8 i, u32 reg, u32 mask, u32 set);
--- a/drivers/pinctrl/mediatek/pinctrl-paris.c
+++ b/drivers/pinctrl/mediatek/pinctrl-paris.c
@@ -574,8 +574,9 @@ static int mtk_hw_get_value_wrap(struct
 ssize_t mtk_pctrl_show_one_pin(struct mtk_pinctrl *hw,
 	unsigned int gpio, char *buf, unsigned int buf_len)
 {
-	int pinmux, pullup = 0, pullen = 0, len = 0, r1 = -1, r0 = -1;
+	int pinmux, pullup = 0, pullen = 0, len = 0, r1 = -1, r0 = -1, rsel = -1;
 	const struct mtk_pin_desc *desc;
+	u32 try_all_type;
 
 	if (gpio >= hw->soc->npins)
 		return -EINVAL;
@@ -589,24 +590,39 @@ ssize_t mtk_pctrl_show_one_pin(struct mt
 		pinmux -= hw->soc->nfuncs;
 
 	mtk_pinconf_bias_get_combo(hw, desc, &pullup, &pullen);
-	if (pullen == MTK_PUPD_SET_R1R0_00) {
-		pullen = 0;
-		r1 = 0;
-		r0 = 0;
-	} else if (pullen == MTK_PUPD_SET_R1R0_01) {
-		pullen = 1;
-		r1 = 0;
-		r0 = 1;
-	} else if (pullen == MTK_PUPD_SET_R1R0_10) {
-		pullen = 1;
-		r1 = 1;
-		r0 = 0;
-	} else if (pullen == MTK_PUPD_SET_R1R0_11) {
+
+	if (hw->soc->pull_type)
+		try_all_type = hw->soc->pull_type[desc->number];
+
+	if (hw->rsel_si_unit && (try_all_type & MTK_PULL_RSEL_TYPE)) {
+		rsel = pullen;
 		pullen = 1;
-		r1 = 1;
-		r0 = 1;
-	} else if (pullen != MTK_DISABLE && pullen != MTK_ENABLE) {
-		pullen = 0;
+	} else {
+		/* Case for: R1R0 */
+		if (pullen == MTK_PUPD_SET_R1R0_00) {
+			pullen = 0;
+			r1 = 0;
+			r0 = 0;
+		} else if (pullen == MTK_PUPD_SET_R1R0_01) {
+			pullen = 1;
+			r1 = 0;
+			r0 = 1;
+		} else if (pullen == MTK_PUPD_SET_R1R0_10) {
+			pullen = 1;
+			r1 = 1;
+			r0 = 0;
+		} else if (pullen == MTK_PUPD_SET_R1R0_11) {
+			pullen = 1;
+			r1 = 1;
+			r0 = 1;
+		}
+
+		/* Case for: RSEL */
+		if (pullen >= MTK_PULL_SET_RSEL_000 &&
+		    pullen <= MTK_PULL_SET_RSEL_111) {
+			rsel = pullen - MTK_PULL_SET_RSEL_000;
+			pullen = 1;
+		}
 	}
 	len += scnprintf(buf + len, buf_len - len,
 			"%03d: %1d%1d%1d%1d%02d%1d%1d%1d%1d",
@@ -624,6 +640,8 @@ ssize_t mtk_pctrl_show_one_pin(struct mt
 	if (r1 != -1) {
 		len += scnprintf(buf + len, buf_len - len, " (%1d %1d)\n",
 			r1, r0);
+	} else if (rsel != -1) {
+		len += scnprintf(buf + len, buf_len - len, " (%1d)\n", rsel);
 	} else {
 		len += scnprintf(buf + len, buf_len - len, "\n");
 	}
@@ -966,6 +984,12 @@ int mtk_paris_pinctrl_probe(struct platf
 
 	hw->nbase = hw->soc->nbase_names;
 
+	if (of_find_property(hw->dev->of_node,
+			     "mediatek,rsel_resistance_in_si_unit", NULL))
+		hw->rsel_si_unit = true;
+	else
+		hw->rsel_si_unit = false;
+
 	spin_lock_init(&hw->lock);
 
 	err = mtk_pctrl_build_state(pdev);
